c - 运算符 [] 的正确输入数据类型是什么？

Question

当访问一个数组时，我们使用运算符[]，如下所示:

int a[5];
...
a[b] = 12;

上面的变量 b 的正确数据类型是什么？

我发现 a[b] 等同于 *(a + b)，这让我觉得我想要 b 为 void* 或 size_t 但我不确定。

Answer 1

来自 C 标准(ISO/IEC 9899:TC2) Sec 6.5.2.1 数组下标

A postfix expression followed by an expression in square brackets [] is a subscripted designation of an element of an array object. The definition of the subscript operator [] is that E1[E2] is identical to (*((E1)+(E2))). Because of the conversion rules that apply to the binary + operator, if E1 is an array object (equivalently, a pointer to the initial element of an array object) and E2 is an integer, E1[E2] designates the E2-th element of E1 (counting from zero).